Stiffening portions of the uppers of shoes



Feb- 1, 1944- R.' P. HOFFERBERT 2,340,591

STIFFENING PORTONS 0F THE UPPERS OF'SHOES Filed July 1, V1942.

`Patented Feb. l, 1944 2,340,591 n STIFFENING' Poa'rIoNs 0F THE UPPEnsSHO Raymond I. Hofierbert, Cambridge, Mass., as-

signor to United Shoe Machinery Corporation, Flemington, N. J., acorporation of New Jersey Application July 1, 1942,- Serial No. 449,227

12 Claims.

This invention relates to the stiffening of parts of the uppers ofshoes, and is in general an improvement upon the invention set forth inapplication Serial No. 388,398, filed April 14, 1941, in the name ofWalter H. Wedger.

According to that application there is incorporated in a selectedlocality of the upper of a `shoe an aminoplast stiffening substance inuncured form, such, for example, as an aqueous solution of aurea-formaldehyde resin, a curing agent capable of causing thestiffening substance to be converted into a form which, when dry, ishard and water-resistant, and a toug ening substance. After the selectedlocality of the upper, for example the toe portion, has had incorporatedin it the stiiening substance, either by incorporating the substancedirectly in a lining member such as the doubler or the lining proper orby incorporating in the upper a separate stiiiener blank containing thesubstance,

the upper is conformed to a last; and, when the stiifening substance hasdried, the toe portion of v the upper of the shoe becomes hard andresilient.

I have found that the use of a lubricating oil as a toughening substanceproduces a stronger and at the same time more'resilient stiiened portionin the finished shoe than do the toughening substances of the priorapplication.

Referring to the accompanying drawing, which is like that of theapplication,

Fig. 1 is a perspective of a portion of the toe Y end of the upper of ashoe, the stifEening material being in process of being applied to thetoe portion of the doubler by means of a spatula;

Fig. 2 is 'a plan of the same portion of the upper showing theapplication of the curing agent in the form of a spray;

Fig. 3 is a perspective of thetoe portion of the upper afterlit has beenpulled over;

Fig. 4 is a perspective of a toe heater showing two lasted shoes inprocess of having their toe portions heated to hasten the drying of thestiiiening material; and

Fig. 5 is a plan of a toe stiiener blank to which the stiffeningmaterial and the curing agen't have been applied, said blank being readyto be incorporated in the toe portion of the upper of a shoe.

The term aminoplast stiening substance, as used herein, denotes awater-soluble product which results from the partial reaction of a.substance containing an NH2 grouplinked to carbon, such as urea,thiourea, melamine, dicyandiamide and derivatives of these substances,with an aldehyde, the product upon having its pH- value changed beingcapable of curing to a waterresistant resin. In the preparation of suchaminoplast stiiening substances, the partial reaction is one of additionor addition plus par tial polymerization. After the addition reaction,the products may be stabilized and Yused as such. Alternatively, theaddition products may be partially polymerized and then stabilized. Inthe nal cure the addition products, or the partially polymerizedproducts, are polymerized to a water-resistant resin. The aminoplaststiiening substances may be any-one of such partial reaction products ora mixture of'any of them.

An aminoplast stiiiening substance which is put out by the AmericanCyanamid Company under the trade name of Beetle Syrup No. 250 conc, andis an aqueous solution of the partial reaction production of urea andformaldehyde containing solids and having a pH value of about 7, is in aconvenient form to be used; and

other partial `reaction products may be made into a solution orsuspension or a combination of the two having the same solid content. Inthe description which follows, such a solution or Suspension will bereferred to as resin syrup.

A formula for th stitfening materiali, as given in the applicationidentified above, is:

The stiffening material of this formula is a pasty mass. The groundhorse hair is a iiller. The triethanol amine is a stabilizer andneutralizes to the desired degree the acidity of the ground horse hair.The nitrocellulose is a toughening agent which increases the exibilityor resilience of the cured resin. Various toughening substances may beemployed such as polyvinyl acetate and asphalt, as well as variousfillers such as leather dust vand ground-slate, as listed in the saidapplication. The pH value of the solution or pasty mass is about '1.

Referring now to the drawing, one manner of using this stiffenlngmaterial will be briefly described. Assuming that the assembled uppercomprises a vamp 1 and lining members including a doubler 9 and a liningproper Il, the stili,-

ening material may be incorporated 'in a desired locality by placingthetoe. portion of the assembled upper upon a at support, with the vampdown and the liningA pulled back as shown in Figure- 1, and forcing thepasty stiffening material l I3 into and through the doubler 9 by meansof a spatula l5. The curing agent may be applied, as shown in Figure 2,by spraying a solution of a substance such as ammonium chloride upon thedoubler or upon the doubler and the exposed margin of the vamp, if themargin of the doubler has been cut away as shown in the drawing. Theammonium chloride, which is a curing agent, reduces the pH value of thepartial reaction product to a range of from 2 to5. The toe portion Cu'.the doubler, treated with the resinous pasty mass and with the curingagent as described above, will remain workable during the time whichelapses in common shoe-factory practice until the shoe is lasted, therapidity of the cure depending upon the pH Value. The assembled upper isconformed to the last and maintained in the shape thus imparted to ituntil the stiffening material has dried, whereupon there results astiffened toe portion of the upper which is hard and resilient. Insteadof making use of a lining member such as the doubler as described above,the stiiening material and the curing agent may be applied to a separatestifiener as indicated in Figure 5, which may be inserted in theassembled upper, the manner in which the stiffening substance andthecuring agent are incorporated in the upper being immaterial. It willbe understood that the stiffening substance, before being treated withthe curing agent to change its pH value, is water-soluble and that theimpregnated lining member or the separate stiifener may -be allowed todry if desired and then wet with an aqueous solution of the curingagent, the water-serving to soften the stiifening substance and thecuring agent changing its pH value. If desired, the toe portion of thelasted shoe may be heated, for example as shown in Figure 5, to hastenthe drying.

The stiffened portion of the upperrof a shoe, for example the toeportion. should be strong and hard so as to offer as great a resistanceas possible to a force tending to deform it, and at the same time shouldbe of a flexibility or resilience such that, if it is deformed, it willimmediately resume its original shape. In other words, the stift'enedportion should be as strong and hard as possible without being brittle.The aminoplast stiffening substances, of which the partial reactionproduct of urea and formaldehyde is a typical example, are, when cured,very hard and strong but also very brittle, the problem being to detractas little as possible from the .strength of these substances and at thesame time to increase their resilience. When such an aminoplaststiffening substance is used as an impregnant for a fabric lbase,particularly when a filler is present, the impregnated fabric possessesmuch more flexibility and resilience than does a film of the stiffeningsubstance alone. It is desirable, however, that the stiifened portionwhile still retaining as much as possible of its hardness and strength,that is, of its capability to resist deformation, should be still moreresilient, and hence the use of a toughening substance. 1

I. have found that lubricating oils used as toughening substances giveimproved results. Various oils such as fixed vegetable oils -of thenon-drying or the drying type, examples of the former being castoroil'andolive oil, and of the latter linseed oil and tung oil; animaloils of which neats-foot oil and sperm oil are examples; and mineraloils such as ,"D. T. E. oil heavy medium of the Standard Oil Company ofNew York the case hitherto.

and Mineral oil," an oil of the same general nature as the D. T. E. oilbut of lower viscosity, may be used, the oil in each case being emulsiedin the resin syrup. In the case of the drying oils, the stiifeningmaterial should -be used within a short time since the emulsion of' suchoils will thicken noticeably upon standing.

Below is an illustrative example of the stiftening material of thepresent invention.

-Preferably about 40 parts by weight of oil are used.

A uniform dispersion is obtained by mixing the resin syrup, thetriethanol amine and the castor oil. A homogeneous emulsion is obtainedby mixing the water with the dispersion. A smooth paste is formed bymixing the emulsion with the filler of ground horse hair which ispreferably i of a flneness to pass through a 1D0-mesh sieve.

It will be understood that other lubricating oils, such as thosementioned above, and mixtures of oils may be used in place of castoroil, and that the particular alkali and filler used is immaterial so faras the present invention is concerned. As to the use of water, there maybe mixed with the water, if desired, a considerable amount of awater-miscible liquid, such for example as alcohol, which is morevolatile than water and which will shorten the drying time.

It should be noted that the aminoplast stiffening substances arewater-soluble products, by which is meant products which are completelysoluble in cold Water and also products which, while only a portioncompletely dissolves, yet retain a suiiicient degree of solubility inthe remainder so that the whole material may be used in an aqueousmedium without requiring a protective colloid to prevent incompletelydissolved fractions settling out and destroying the uniform, homogeneouscharacter of. the fluid material. For instance, products arecharacterized as Water-soluble which, in the form of a fine powder andwithout the addition of a protective colloid, may be mixed with water toform a syrupy liquid which may lbeapplied to a fibrous base and whendried will provide an adherent substance of a homogeneous character.

I am unable to explain exactly how the oil acts, but a possibleexplanation may be that it acts both to increase the flexibility andtoughness of the resin by lubricating the molecules thereof and also tolubricate the fibers of the fabric. In any event the stiffened portionof the upper of the shoe is more resistant to deformation and at thesame time more resilient than has been Having thus described'theinvention, what I claim as new and desire to secure by Letters Patent ofthe United States is:

1. The method of stiffening af portion of the upper of a shoe, saidmethod comprising incorporating in a selected locality of the upper anaminoplast stiifenng substance in uncured form in a liquid vehicle, acuring agent capable of causing the substance to vbe converted into aform which, when dry, is hard and water-resistant and. a tougheningsubstance in the form of an emulsified lubricating oil, imparting to theselected locality of the upper the desired shape, and maintaining saidshape while the stiiening substance hardens, said aminoplastv stiileningsubstance being chosen from a class vconsisting of they partial reactionproducts of urea, thiourea, melamine, dicyandiamide and derivatives ofthese substances with an aldehyde, and said oil being at least 20% byweight of the solid stiiening substance.

2. The method of stiening a portion of the upper of a shoe, said methodcomprising incorporating in a selectedlocality of the upper anaminoplaststiiening substance in uncured form in a liquid vehicle, a curing agentcapablerof causing the substance to be converted into a form which, whendry, is hard and water-resistant, a toughening substance in the form ofan em'ulsifled the desired shape, and maintaining said shape lubricatingoil and a ller, imparting to the sel lected locality of the upper thedesired shape, and

maintaining said shape while the stiffening substance hardens, saidaminoplast stilening su-bstance being chosen from a class consisting ofthe partial reaction products of urea, thiourea, melamine, dicyandiamideand derivatives of these substances with an aldehyde, and said oil beingat least by weight of the solid stiffening substance.

3. The method of stiifening a portion of the upper of a shoe, saidmethod comprising `incorporating in a selected locality of the upper anaminoplast stiffening substance in uncured form, a curing agent capableof causing the substance to be converted into a form which, when dry, ishard and water-resistant, a toughening substance in the form of anemulsiled vegetable lubricating oil and a filler, imparting to theselected locality of the upper the desired shape, and

while the stiffening substance hardens, said aminoplast stiieningsubstance being chosen from a class consisting oiA the partial reactionproducts of urea, thiourea, melamine, dicyandiamide and derivatives ofthese substances with an .,aldehyde, and said oil being at least 20% byweight of the solid stirening substance.

7. The method of stifiening a portion of the upper of a shoe, saidmethod comprising incor-v porating in aselected locality of the upper astiffening substance in incompletely polymerized condition in an aqueousvehicle, a curing agent adapted to cause the polymerization to proceedand an emulsified lubricating oil, said stiffening substance beingchosen from a .class consisting y of the partial reaction products ofurea, thiomaintaining said shape while the stiffening subv stancehardens, said aminoplast stiiening substance being chosen from a classconsisting of the partial reaction products of urea, thiourea,-melamine, dicyandiamide and derivatives of these substances with analdehyde, and said oil being at least 20% by weight of the solidstiiening substance.

4. The method of stiffening a portion of the upper of a shoe, saidmethod comprising incorporating in a selected locality of the upper anaminoplast stiiening substance in uncured form, a curing agent capableof causing the substance to be converted into a form which, when dry, ishard and water-resistant, a toughening substance in the form of emulsiedcastor oil 'and a ller, imparting ,to the selected locality of the upperthe desired shape, and maintaining said'shape while the stiieningsubstance hardens, said aminoplast stiiening substance being chosen froma class consisting of the partial reaction products of urea, thiourea,melamine, dicyandiamide and derivatives of these substances with analdehyde, and said oil being at least 20% by weight of the solidstiening substance.

5. The method of stiiening a selected portion of the upper of a shoe,said method comprising incorporating in a fabric lining member of anupper an aqueous solution of an aminoplast stiening substance in uncuredform, a curing agent capable of causing the substance to be convertedinto a form which, when dry, is hard and waterresistant and an emulsiedlubricating oil, im-

parting to the selected portion of the upper the desired shape, andmaintaining said shape while the stiiening substance hardens, saidaminoplast stiening substance being chosen from a class consisting ofthe partial reaction products of urea, thiourea, melamine, dicyandiamideand deurea, melamine, dicyandiamide and derivatives of these substances,with an aldehyde, imparting to the selected locality of the upper thedesired shaipe, and maintaining said shape while the stiiening substancehardens, and said oil being at' least 20% by weight of the solidstiiening substance.

8. A shoe upper ready to be conformed to a last, there beingincorporated in a selected locality thereof a stiffening materialcomprising an aminoplast stiffening substance in uncured form in aliquid vehicle, a toughening substance in the form of an emulsiedlubricating oil, and a cur'v ing agent, said aminoplast stiffeningsubstance being chosen from a class consisting of the partial reactionproducts of urea, thiourea, melamine, dicyandiamide and derivatives ofthese substances with an aldehyde. and said oil being at least 20% byWeight of the solid stiffening substance.

9. A shoe upper ready to be conformed toa last, there being incorporatedin a selected locality thereof a stiiening material comprising anaminoplast stifening substance in uncured form in a liquid vehicle, atoughening substance in the form of an emulsified lubricating' oil, anda curing agent, the lubricating oil being at least 25% by weight of thesolid stiening substance, said aminoplast stiifening substance beingchosen from a class consisting of the partial reaction products of urea,lthiourea, melamine, dicyandiamide and derivatives of these substanceswith an aldehyde.

l0. A shoe having a stiffened toe portion containing a cured aminoplaststiiening substance, a lubricating oil, and a filler, said aminoplaststiiening substance being chosen from a class consisting of the partialreaction products of urea, thiourea, melamine, dicyandiamide andderivatives of these substances with an aldehyde,

'and said oil being at least 2,0% by Weight of the solid stiffeningsubstance.

11. A shoe part comprising a fabric base carrying a stiffening substancestabilized in incompletely polymerized form and a lubricating oil, saidstiiening substance being chosen from a said stiiening substance beingchosen from a class consisting of the partial reaction products of urea,thiourea, melamine, dicyandiamide and derivatives of these substances.with an aldehyde, the lubricating oil being at least 25% by Weight ofthe stiiening substance.

RAYMOND P. HOFFERBERT.

